Protection of the earth's ozone layer has recently been mandated by the federal government Refrigerant and fire-extinguisher Halon is now removed from refrigerant devices using a recovery device. These devices typically use a compressor to draw the refrigerant from the system to be emptied. The recovery device then condenses the refrigerant which is then piped to an external, small portable storage tank. These tanks become quite hot, however, during the recovery operation. Since the refrigerant inside the tank is at saturated conditions, this warm tank causes an increased high-side (condenser) pressure. The result of a higher condenser pressure is a decrease in the rate of refrigerant recovery. This is a critical problem since recovery rate of portable units are already slow.
Simply immersing the storage tank in ice-water would lower the storage tank temperature and therefor the storage tank pressure, thereby improving the recovery rate. Maintaining sufficient ice during an 8-hour work day is, however, difficult because the user would have to carry a large pail to contain the storage tank and ice-water mixture. Another approach would be to use a one-time endothermic (salt-water) chemical cooling reaction.
An object of the present invention is to solve the foregoing problems by using a phase-change material contained in flexible material which can be wrapped around the tank. The use of a phase-change material in a vest to be worn by a person is disclosed in U.S. Pat. No. 4,856,294. Rather than use ice which cannot be refrozen unless it is cooled below 32.degree. F., the present invention contemplates the use of individual packs containing phase-change material held in a cloth device which wraps around the storage tank. These packets contain a phase-change material which melts in the range of 40.degree.-95.degree.0 F., thereby providing the necessary storage tank cooling. During a typical refrigerant recovery, the storage tank external surface temperature exceeds 135.degree. F. Cooling to below 80.degree. significantly improves the recovery rate, and the colder the storage tank the greater the recovery rate.